The invention pertains to new materials for the improvement of the electron injection and the electron transport in organic components like organic light-emitting diodes (OLED's), organic field effect transistors (OFET's), and organic solar cells.
In recent years materials, in particular for organic light-emitting diodes, have become known, which improve electron injection and electron transport in OLED's. (Lit.: S. Yamaguchi, S. Akiyama, K. Tamao, J. Am. Chem. Soc. 2000, 122 6335-6336).
This also results in a lower operating voltage without affecting the efficiency of the OLED. These materials are strong electron donors, which are doped in small quantities into the electron transport layer or the emitter layer of the OLED. Such additions facilitate the reduction of the electron transport material or emitter material (i.e. acceptance of electrons into the LUMO [lowest unoccupied molecular orbital] of the electron or emitter material), which otherwise takes place due to the energy of the electric field only. As a result, a weaker electric field (i.e. a lower operating voltage) achieves the same efficiency.
In the currently known materials, the stability and the injection as well as the electron-facilitating effect are not satisfactory yet.